Audio actuated lamp

ABSTRACT

A system for electrically energizing a load, such as a lamp, upon receipt of an acoustic signal having predetermined characteristics, the system comprising a connector for an alternating current power source, acoustic pick-up, and a triggering device for supplying alternating current to the load. The improvement comprises a rectifier for providing a direct current output to be used by the control portion of the system, an amplifier for amplifying the output of the acoustic pick-up, and a time delay circuit for establishing a time period throughout the length of which the signal from the pick-up must exist in order to energize the load. The time delay circuit may include circuit components for activating the triggering device to supply alternating current to the load when such a predetermined signal is received for such a predetermined time duration. My system may also include a light detector for providing an electrical output controlling either the amplifier or the time delay circuit such that the load will be energized only when there is a combination of such a predetermined acoustic signal and an established light condition.

United States Patent 1 Hopkins 1 1 AUDIO ACTUATED LAMP Charles L. Hopkins, 86 Beechwood, Shelbyville, Ky. 40065 22 Filed: Apr. 5, 1974 21 Appl. No.: 458,081

[76] Inventor:

[S2] U.S. Cl. 340/148; 340/366 8 [51] Int. (11. G08B 5/22 [58] Field of Search... 340/148, 261, 167 A, 171 R, 340/366 B; 84/464; 307/117; 317/147, 124;

Primary Examiner-Harold l. Pitts Attorney, Agent, or FirmWilliam R. Coffey 1 July 1, 1975 5 7 ABSTRACT A system for electrically energizing a load, such as a lamp, upon receipt of an acoustic signal having predetermined characteristics, the system comprising a connector for an alternating current power source, acoustic pick-up, and a triggering device for supplying alternating current to the load. The improvement comprises a rectifier for providing a direct current output to be used by the control portion of the system, an amplifier for amplifying the output of the acoustic pick-up, and a time delay circuit for establishing a time period throughout the length of which the signal from the pick-up must exist in order to energize the load. The time delay circuit may include circuit components for activating the triggering device to supply alternating current to the load when such a predetermined signal is received for such a predetermined time duration. My system may also include a light detector for providing an electrical output controlling either the amplifier or the time delay circuit such that the load will be energized only when there is a combination of such a predetermined acoustic signal and an established light condition.

17 Claims, 6 Drawing Figures m E-WFUJUH I975 9893081 SHEET 2 ID i T RESET k 1 POWER 3 TIMER SUPPLY 52.59 as F 4 30 OFF so FT ACOUSTIC Low TIME ON TRIGGERING PASS AMP START DEV'CE 1 AUDIO ACTUATED LAMP BACKGROUND OF THE INVENTION 1. Field of the Invention My present invention relates to control circuits and more particularly to the provision of the control system for electrically energizing a load, such as a lamp, upon receipt of an acoustic signal having predetermined characteristics or upon the receipt of such a signal during pre-established light conditions or upon a change in light conditions.

2. Description of the Prior Art Acoustically-actuated control systems are known and are shown in the prior art. See, for instance, U.S. Pat, Nos. 270,083; 1,844,117; 2,401,955; and 3,579,187. The U.S. Pat. 270,083 (Filed under the Act of Mar. 3, 1883, as amended Apr. 30, 1928; 370 O.G. 757) discloses what is referred to as a sound-actuated relay comprising a microphone, the electrical output of which is supplied to the grid of a vacuum tube. When the microphone picks up sound, the signal applied to the tube grid causes sufficient conduction to actuate a relay to close a circuit. That is one type of acousticallyoperated control circuit. The other type which is shown in the other patents listed includes a relay which is sensitive to sound and which will, upon the receipt of such a sound, vibrate to close a circuit.

SUMMARY OF THE INVENTION My system, I believe, is a significant improvement over such prior art devices for several reasons. First I incorporate in my system a light detection means such that the load will be energized only when a proper acoustic signal is received and a pre-established light condition exists. My system may be constructed such that the load will be energized, for instance, when the light level changes from a relatively high ambient light condition to a relatively low ambient light condition or vice versa. In other words, my present invention comprises a control system for energizing a load when a proper acoustic signal is received and/or when a preestablished light condition exists or there is a change in such a condition. Secondly, I provide a time delay means to require the acoustic signal to have at least a certain duration in order to activate the system. Thirdly, the sensitivity of my system can be adjusted.

It is an object of my invention, therefore, to provide a system for electrically energizing a load upon receipt of an acoustic signal having predetermined characteristics, the system comprising means providing a connection to an alternating current power source, acoustic pick-up means, and a triggering device for supplying alternating current to the load, and wherein the improvement comprises rectifier means for providing a direct current output, means for amplifying the output of the acoustic pick-up means, and means for establishing a time delay period throughout the length of which the signal from the pick-up means must exist in order to energize the load, the time delay means including means for activating the triggering device to supply alternating current to the load when such a predetermined acoustic signal is received for such a predetermined time duration.

It will be appreciated, as this specification progresses, that the triggering device may take several different forms. For instance, I may use a Triac as a triggering device and an SCR which is turned on by the time delay means to supply gating current to the Triac. Also, I may have the timing circuit include, for instance, a unijunc tion transistor and then connect the output of the unijunction transistor to the gate of the Triac by means of a transformer or some other such electrical device.

My system is ideally suited for slowly turning on a lamp in a bedroom or any other room for that matter, for instance, when the phone rings or the alarm clock rings and it is dark in the room. The slow turn-on or soft-start, as I call it, is designed to reduce the possibility of frightening a sleeping person by the sudden illumination of a lamp. Other such uses for my system will become apparent as this description progresses.

To the accomplishment of the above and related objects, this invention may be embodied in the forms illus trated in the accompanying drawings, attention being called to the fact, however, that the drawings are illustrative only, and that changes may be made in the specific constructions illustrated and described, so long as the scope of the appended claims is not violated.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the drawings:

FIG. I is a schematic view of one illustrative embodiment of the present invention;

FIG. 2 is a schematic view of another illustrative embodiment of the present invention;

FIG. 3 is a schematic of a portion of still another illus trative embodiment;

FIG. 4 is a perspective view of a lamp, telephone and alarm clock sitting on a table;

FIG. 5 is a block diagram of still another embodiment, and

FIG. 6 is a block diagram of still another embodiment of the present invention.

Referring particularly to the drawings, like reference numerals representing like parts in the various figs, it will be seen that FIG. 1 shows a detailed schematic, the alternating current power terminals being indicated at l0, 12. A conventional 60-cycle per second alternating current power source may be applied to such terminals 10, 12. Diode l4, resistor 16, capacitor 18, resistor 20 and zener diode 22 comprise a half-wave rectified direct current power supply means or rectifier means indicated generally by the reference numeral 24. The positive half-cycle of the alternating current line voltage is fed through diode 14 and resistor 16 to capacitor 18. The capacitor 18 and resistor 20 serve to filter the half-wave rectified voltage. The zener diode 22 then regulates the filtered voltage to a constant direct cur rent level.

Transistors 26, 28 form a high-gain Darlington connected amplifier means indicated generally at 30. Resistor 32 is used to bias the amplifier means in the desired operating region. Resistor 34 serves as a load resistor for the amplifier means. The audio pick-up means 36 is connected to the base of the transistor 26 as illustrated. A capacitor 38 is used for safety purposes in that it will limit the leakage current to a safe value in the event the pick-up means 36 is constructed such that an exposed metal part may be inadvertently connected to ground. In the illustrative embodiment of FIG. 1, it is assumed that the negative terminal of the pick-up means 36 is accessible and the positive terminal is sufficiently insulated.

The components including the capacitor 40, capacitor 42, and diodes 44, 46 are used to store a negative voltage on the capacitor 42. This negative voltage will be present whenever an input signal exists at the base of transistor 26 and is used to bias off the transistor 48. A resistor 50 is used to bias on the transistor 48 in the quiescent condition and to provide a predetermined rate of discharge for the capacitor 42 when the system is in the active state. Components including resistor 52 which may be adjustable, capacitor 54, unijunction transistor 56, and resistor 58 comprise an unijunction transistor timing circuit. Whenever the voltage at the unijunction emitter is allowed to reach a certain value (V then the unijunction transistor turns on and discharges the capacitor 54 through the resistor 58 in par allel with the SCR 62 gate circuit. A photocell 60 is connected in parallel with the capacitor 54 between the emitter of the unijunction transistor 56 and ground.

When turned on by the transistor 56, the SCR 62 furnishes current to the Triac 64 gate circuit turning the Triac on also. Resistor 66 is used to limit the current to the Triac gate. Capacitor 68 and resistor 70 are used for noise suppression purposes. A switch 72 is used manually to reset the SCR 62 to the off state and thus turn off the Triac 64.

Resistor 74 and capacitor 76 are used to minimize the effect of the line voltage transients on the Triac 64. The photocell 60 may be used to prevent application of voltage to the load during periods of high ambient light conditions when connected as shown in FIG. I. This may be desirable if the load is a lamp and it is required to be turned on only during darkness or at some predetermined low light level. In this condition, the emitter voltage of transistor 56, due to the divider action between resistor 52 and the low resistance of the photocell 60, will be insufficient to allow transistor 56 to turn on. A switch 78 may be used to bypass the control system and to allow the load to be manually energized by another switch 80 if desired. In FIG. I, I show the load as a light 82.

It will be appreciated, however, that the load 82 may take several different forms.

Assume that the electrical signal produced by the acoustic pick-up means 36 initially goes negative to the base of the transistor 26. This negative-going signal tends to turn off the amplifier means 30. The voltage at the junction of resistor 34 and capacitor 40 then goes positive and capacitor 40 charges through resistor 34 and diode 44 to this positive voltage. On the succeeding positive half-cycles of the input signal, the amplifier means will tend to conduct and thus place the voltage existing on capacitor across the diode 46 and capacitor 42. Capacitor 40 is then discharged through the diode 46 into capacitor 42 until their voltages are equal. This voltage on capacitor 42 is of such polarity as to render transistor 48 nonconductive. During the negative half-cycle of the input signal, this negative voltage on capacitor 42 tends to leak off through the resistor 50. However, by proper choice of the time constants for resistor and capacitor 42, this negative voltage can be adjusted to decay at such a rate that it will not have time to diminish to the extent that transistor 48 will become conductive prior to once again re ceiving a transfer of voltage from capacitor 40 on the following positive half-cycle of the input signal. With transistor 48 turned off, the emitter voltage of transistor 56 is allowed to reach the said V by virtue of capacitor 54 charging through resistor 52. This is assuming that the photocell 60 resistance is high due to lowlevel ambient light conditions. Resistor 52 may be made variable such that the system sensitivity can be changed as illustrated in FIG. 1. For example, decreasing resistor 52 allows the capacitor 54 quickly to charge to the said V, of transistor 56 and thus energize the load. Increasing resistor 52 has the opposite effect. Thus, by varying resistor 52, the system can be made to respond to any predetermined input signal duration, while rejecting those signals of shorter duration. Once the transistor 56 emitter voltage has reached V,,, the transistor 56 turns on thus discharging capacitor 54 and thereby rendering the SCR 62 conductive. The SCR 62 then furnishes gate current to the Triac 64 making it conductive also and applying the alternating current line voltage to the load 82.

Referring further to FIG. 1, it will be appreciated that the photocell could be placed in series with resistor 52. This would have the effect of causing the load to be energized only during periods of daylight or relatively high ambient light conditions. It would also have the effect of enabling the circuit to respond to shorter time duration signals as the ambient light level is increased, or conversely, responding to longer duration signals as the light level is decreased.

Referring to FIG. 2, like reference numerals representing like parts, I have shown a somewhat different circuit arrangement that is extremely sensitive to short duration low-level acoustic signals. Its operation is similar to that described for FIG. 1, the primary difference being the elimination of the unijunction transistor 56 for triggering and timing purposes. In addition, the load can be energized by the sudden illumination of the photocell 60 as well as by an acoustic signal. The acoustic signal system, however, is effective in energizing the load only during periods of darkness or very low ambient light levels. In FIG. 2, I show a diode 84 connected in the gate circuit of the SCR 62 and a resistor 86 connected between that gate circuit and ground.

FIG. 3 shows an input arrangement for the circuitry of FIG. 2, whereby the acoustic signal is effective for energizing the load only during periods of relatively high ambient light levels. Also, in the arrangement of FIG. 3, the load may be energized by the sudden removal of the ambient light from the photocell 60. In FIG. 3, I show terminal points 88, 90, 92, 94, 96. Terminal 88 may be connected to the junction of resistor 20 and zener diode 22, and terminal 90 may be connected to terminal 12 as shown in FIG. 2 while the circuitry to the right of terminals 92, 94, 96 may be the same as circuitry to the right of the amplifying means 30 in FIG. 2.

With those circuit details in mind, I now refer to FIG. 4 which shows a lamp 102, a telephone 104, and an alarm clock 106 all sitting on a table. The lamp 102 may include the light bulb indicated at 82 in the drawings. When either the telephone 104 rings or the alarm clock I06 rings, the acoustical signal generated by such ringing will turn on the lamp 102. Of course, if it is during a period of relatively high ambient light conditions, the lamp would not be needed and would not be energized by such a phone or alarm clock.

In FIG. 5, I show a block diagram of the type of system discussed in conjunction with FIGS. 1-3 and in addition I show a block for a soft-start circuit I10 and a low pass filter and a timer T. The soft-start circuit may include means for slowing down the turning on of the load 82. For instance, the circuit 110 may include circuitry that, when used in conjunction with a unijunction transistor and thyristor, or other such devices, will be effective to cause the lamp 102 (load 82) to come on slowly, thereby not to frighten a person sleeping in the room.

The timer T may consist of a solid state programmable timing means that will reset itself to shut off the light 82 at the completion of the selected timing cycle. Such a timing means may be placed, for instance, be tween the time delay circuit and the soft-start circuit as shown in FIG. 5, or between the time delay means and the triggering device.

Turning now to FIG. 6, it will be seen that I show another block diagram of the system including the softstart feature as well as a filter system including an inductor 120 and a capacitor [22. The system of FIG. 6 also includes a resistor 124 in series with the Triac 64. There is a coil 126 of a transformer between the gate of the Triac 64 and ground as illustrated. The resistor 124 is necessary to protect the Triac 64 under condi tions of flash over." Such a condition exists when the lamp filament burns open and an arc is developed between the open filament leads due to the gas ironizing inside the envelope. At this time, the current would be limited only by the line impedance if] did not have the resistor 124. lnductor I and capacitor 122 constitute a radio frequency interference (RFl) filter, and tend to prevent line transients from getting through to trigger the time delay circuitry. Also, the RFI filter will suppress the RFI that is generated by the Triac and thus prevent noise from being on the line to the extent that it would be objectionable when other household appliances such as the radio or television are being used.

in the system of FIG. 6, I use the unijunction transistor 56 to trigger the Triac 64. A resistor 128 is in the B, electrode circuit and a primary coil 130 of the said transformer is in the B electrode circuit. When the transistor 56 conducts, current flow in the coil 130 will induce current flow in the coil 126 to turn on the Triac The filter shown in FIGS. 5 and 6 between the acoustic pick-up 36 and the amplifier 30 may preferably be a low-pass filter designed to by-pass any high frequency signals outside the acoustic range of alarm clocks and telephones to eliminate nuisance turn-ons of the lamp 82. It will be appreciated that such a filter, which is quite conventional and need not be discussed in detail, may be eliminated if it is desired that the lamp 82 be turned on in response to acoustic signals of a wide range.

The system shown may be placed in an adapter box that plugs into a 60 cycle per second alternating current outlet and used to energize any appliance within its rating. Any appliance can be started with my system by the ringing of a phone or alarm clock.

The timer T is programmable at the discretion of the user of my system. My preferred timer T is one that will reset itself upon completion of the timing cycle.

it will be appreciated that my system may be provided as an adapter, i.e., with all the electronics in a small box that plugs into a 60H outlet. Then, any household appliance within the power rating can be turned on by the ringing of a phone or an alarm clock if the user desires.

I claim:

l. A system for electrically energizing a load upon re ceipt of an acoustic signal having predetermined characteristics including a fundamental frequency in addition to all significant harmonics thereof of the type typically generated by the sound of an alarm clock, telephone and the like, said system comprising means providing a connection to an alternating current power source, acoustic pick-up means, and a triggering device for supplying alternating current to said load, wherein the improvement comprises rectifier means for providing a direct current output to trigger on said triggering device, said rectifier means being connected to said alternating current power source connecting means, means for amplifying the output of said acoustic pickup means, said amplifier means being connected to said rectifier means, means for establishing a minimum time delay period throughout the length of which the signal from the pick-up means must exist in order to energize the load, said amplifier means connecting the pick-up means to said time delay means, and said time delay means including means for activating said triggering device to supply alternating current to said load when such a predetermined acoustic signal is received for such a predetermined minimum time duration.

2. A system for electrically energizing a load by an acoustic signal having predetermined characteristics, said system comprising means providing a connection to an alternating current power source, acoustic pickup means, and a triggering device for supplying alternating current to said load, wherein the improvement comprises rectifier means for providing a direct current output, said rectifier means being connected to said alternating current power source connecting means, means for amplifying the output of said acoustic pickup means, said amplifier means being connected to said pick-up means and said rectifier means, means for detecting light level, said light level detection means providing an electrical output corresponding to the light level impinging thereon, said light level detection means being operatively connected to said amplifier means such that the output of said amplifier means is controlled by said detection means, and circuit means for operatively connecting said amplifier means to said triggering means, said circuit means including means for activating said triggering device to supply current to said load when such an acoustic signal is received and a predetermined light level exists.

3. The invention of claim 1 in which said load is a lamp, said improvement including means for detecting the light level and providing an electrical output corresponding to the light level, said detection means being connected in the system to prevent energizing the lamp when the light level exceeds a predetermined level.

4. The invention of claim 1 including means for detecting the light level and providing an electrical output corresponding to the light level, said detection means being connected in the system to make the activation of said triggering device dependent on the light level as well as the presence of such an acoustical signal.

5. The invention of claim 1 in which the triggering device is a Triac, and including an RFI filter for preventing line transients from triggering the time delay means and for suppressing the RFI generated by said Triac.

6. The invention of claim 1 in which said load is a lamp and said system includes means for slowing down the illumination of said lamp, the last said means being operative in conjunction with said triggering device.

7. The invention of claim 4 in which said detection means includes a photocell, the resistance of which is dependent upon the amount of light impinging thereon, said photocell having a relatively high resistance in relatively low level light conditions and relatively low resistance in relatively high ambient light conditions, said photocell being operatively connected to said time delay means and arranged to prevent operation of said time delay means during conditions of relatively high ambient light.

8. The invention of claim 4 in which said detection means includes a photocell, the resistance of which is dependent upon the amount of light impinging thereon, said photocell having a relatively high resistance in rel atively low level light conditions and relatively low resistance in relatively high ambient light conditions, said photocell being operatively connected to said time delay means and arranged to permit operation of said time delay means only during conditions of relatively high ambient light.

9. The invention of claim 4 in which said detection means includes a photocell, the resistance of which is dependent upon the amount of light impinging thereon, said photocell having a relatively high resistance in relatively low level light conditions and relatively low resistance in relatively high ambient light conditions, said photocell being operatively connected to the input of said amplifier means and arranged to control said am plifier means to cause operation of said triggering device when said photocell is suddenly illuminated.

10. The invention of claim 2 in which said light level detection means includes a photocell, the resistance of which is dependent upon the amount of light impinging thereon, said photocell having a relatively low resistance in conditions of relatively high ambient light and relatively high resistance in conditions of relatively low ambient light.

11. The invention of claim 10 in which said photocell is connected to said time delay means and arranged such that the load will be energized only during conditions of relatively high ambient light.

12. The invention of claim 10 in which said photocell is arranged with said amplifier means such that said triggering device is activated to energize said load when said photocell is illuminated.

13. The invention of claim 10 in which said photocell is arranged with said amplifier means such that said triggering device is activated to energize said load only when relatively high light conditions exist and when the light conditions suddenly are reduced to low level light conditions.

14. The invention of claim 1 including programmable timer means for deenergizing the load a predetermined time after it is energized.

15. The invention of claim 2 including programmable timer means for deenergizing the load a predetermined time after it is energized.

16. The invention of claim 1 including low-pass filter means for by-passing signals having frequency higher than a predetermined range.

17. The invention of claim 2 including low-pass filter means for bypassing signals having frequency higher than a predetermined range, 

1. A system for electrically energizing a load upon receipt of an acoustic signal having predetermined characteristics including a fundamental frequency in addition to all significant harmonics thereof of the type typically generated by the sound of an alarm clock, telephone and the like, said system comprising means providing a connection to an alternating current power source, acoustic pick-up means, and a triggering device for supplying alternating current to said load, wherein the improvement comprises rectifier means for providing a direct current output to trigger on said triggering device, said rectifier means being connected to said alternating current power source connecting means, means for amplifying the output of said acoustic pick-up means, said amplifier means being connected to said rectifier means, means for establishing a minimum time delay period throughout the length of which the siGnal from the pick-up means must exist in order to energize the load, said amplifier means connecting the pick-up means to said time delay means, and said time delay means including means for activating said triggering device to supply alternating current to said load when such a predetermined acoustic signal is received for such a predetermined minimum time duration.
 2. A system for electrically energizing a load by an acoustic signal having predetermined characteristics, said system comprising means providing a connection to an alternating current power source, acoustic pick-up means, and a triggering device for supplying alternating current to said load, wherein the improvement comprises rectifier means for providing a direct current output, said rectifier means being connected to said alternating current power source connecting means, means for amplifying the output of said acoustic pick-up means, said amplifier means being connected to said pick-up means and said rectifier means, means for detecting light level, said light level detection means providing an electrical output corresponding to the light level impinging thereon, said light level detection means being operatively connected to said amplifier means such that the output of said amplifier means is controlled by said detection means, and circuit means for operatively connecting said amplifier means to said triggering means, said circuit means including means for activating said triggering device to supply current to said load when such an acoustic signal is received and a predetermined light level exists.
 3. The invention of claim 1 in which said load is a lamp, said improvement including means for detecting the light level and providing an electrical output corresponding to the light level, said detection means being connected in the system to prevent energizing the lamp when the light level exceeds a predetermined level.
 4. The invention of claim 1 including means for detecting the light level and providing an electrical output corresponding to the light level, said detection means being connected in the system to make the activation of said triggering device dependent on the light level as well as the presence of such an acoustical signal.
 5. The invention of claim 1 in which the triggering device is a Triac, and including an RFI filter for preventing line transients from triggering the time delay means and for suppressing the RFI generated by said Triac.
 6. The invention of claim 1 in which said load is a lamp and said system includes means for slowing down the illumination of said lamp, the last said means being operative in conjunction with said triggering device.
 7. The invention of claim 4 in which said detection means includes a photocell, the resistance of which is dependent upon the amount of light impinging thereon, said photocell having a relatively high resistance in relatively low level light conditions and relatively low resistance in relatively high ambient light conditions, said photocell being operatively connected to said time delay means and arranged to prevent operation of said time delay means during conditions of relatively high ambient light.
 8. The invention of claim 4 in which said detection means includes a photocell, the resistance of which is dependent upon the amount of light impinging thereon, said photocell having a relatively high resistance in relatively low level light conditions and relatively low resistance in relatively high ambient light conditions, said photocell being operatively connected to said time delay means and arranged to permit operation of said time delay means only during conditions of relatively high ambient light.
 9. The invention of claim 4 in which said detection means includes a photocell, the resistance of which is dependent upon the amount of light impinging thereon, said photocell having a relatively high resistance in relatively low level light conditions and relatively low resistance in relatively high ambient light coNditions, said photocell being operatively connected to the input of said amplifier means and arranged to control said amplifier means to cause operation of said triggering device when said photocell is suddenly illuminated.
 10. The invention of claim 2 in which said light level detection means includes a photocell, the resistance of which is dependent upon the amount of light impinging thereon, said photocell having a relatively low resistance in conditions of relatively high ambient light and relatively high resistance in conditions of relatively low ambient light.
 11. The invention of claim 10 in which said photocell is connected to said time delay means and arranged such that the load will be energized only during conditions of relatively high ambient light.
 12. The invention of claim 10 in which said photocell is arranged with said amplifier means such that said triggering device is activated to energize said load when said photocell is illuminated.
 13. The invention of claim 10 in which said photocell is arranged with said amplifier means such that said triggering device is activated to energize said load only when relatively high light conditions exist and when the light conditions suddenly are reduced to low level light conditions.
 14. The invention of claim 1 including programmable timer means for deenergizing the load a predetermined time after it is energized.
 15. The invention of claim 2 including programmable timer means for deenergizing the load a predetermined time after it is energized.
 16. The invention of claim 1 including low-pass filter means for by-passing signals having frequency higher than a predetermined range.
 17. The invention of claim 2 including low-pass filter means for by-passing signals having frequency higher than a predetermined range. 